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Wednesday, 29 January 2014

There has been a heated debate between Judith Curry (Climate Etc.) and Tamino (Open Mind) about the temperature in the Arctic. This debate was initiated by Curry's testimony before congress two weeks ago.

In her testimony Judith Curry quotes:

“Arctic temperature anomalies in the 1930s were apparently as large as those in the 1990s and 2000s. There is still considerable discussion of the ultimate causes of the warm temperature anomalies that occurred in the Arctic in the 1920s and 1930s.” (AR5 Chapter 10)

Tamino at Open Mind investigated this claim and found that recent temperatures were clearly higher as in the beginning of the 20th century. In his post (One of) the Problem(s) with Judith Curry Tamino concludes that the last IPCC report and Curry's testimony are wrong about the Arctic temperature increase:

"I think the IPCC goofed on this one — big-time — and if so, then Curry’s essential argument about Arctic sea ice is out the window. I’ve studied the data. Not only does it fail to support the claim about 1930s Arctic temperatures, it actually contradicts that claim. By a wide margin. It ain’t even close."

That sounded convincing, but I am not so sure about the IPCC any more.

Tamino furthermore wonders where Curry got her information from. I guess he found it funny that Judith Curry would quote the IPCC as a reliable source without checking the information. Replying to another question of mine, Judith Curry replied on twitter that she indeed got her information from the last (draft) IPCC report:

Later she also wrote a reply on her blog, Climate Ect., starting with the above quote from the IPCC report.

Then the story takes a surprising turn, when Steve Bloom hidden in a large number of comments at AndThenTheresPhysics notes that the quote is missing important context. The full paragraph in the IPCC namely reads (my emphasis and the quote in Curry's testimony in red):

A question as recently as six years ago was whether the recent Arctic warming and sea ice loss was unique in the instrumental record and whether the observed trend would continue (Serreze et al., 2007). Arctic temperature anomalies in the 1930s were apparently as large as those in the 1990s and 2000s. There is still considerable discussion of the ultimate causes of the warm temperature anomalies that occurred in the Arctic in the 1920s and 1930s (Ahlmann, 1948; Veryard, 1963; Hegerl et al., 2007a; Hegerl et al., 2007b). The early 20th century warm period, while reflected in the hemispheric average air temperature record (Brohan et al., 2006), did not appear consistently in the mid-latitudes nor on the Pacific side of the Arctic (Johannessen et al., 2004; Wood and Overland, 2010). Polyakov et al. (2003) argued that the Arctic air temperature records reflected a natural cycle of about 50–80 years. However, many authors (Bengtsson et al., 2004; Grant et al., 2009; Wood and Overland, 2010; Brönnimann et al., 2012) instead link the 1930s temperatures to internal variability in the North Atlantic atmospheric and ocean circulation as a single episode that was sustained by ocean and sea ice processes in the Arctic and north Atlantic. The Arctic wide temperature increases in the last decade contrast with the episodic regional increases in the early 20th century, suggesting that it is unlikely that recent increases are due to the same primary climate process as the early 20th century. IPCC(2014, draft, page 10-43 to 10-44).

Steve Bloom dryly comments: "So it was a question in 2007." In other words, the IPCC was right, but Judith Curry selectively quoted from the report. That first sentence is very important, also the age of the references could have revealed that this paragraph was not discussing the current state-of-the-art. The data of the last six years makes a large difference between "with some goodwill in the same range of temperatures" to "clearly higher Arctic temperatures".

This is illustrated by one of the figures from Tamino's post, presenting the data:

And the misquotation is not for lack of space in the testimony. In her blog post, Curry quotes may sections of the IPCC report at length and also the entire paragraph like it is displayed here, just somehow without the first sentence printed here in bold, the one that provides the important context.

Also Robert Way contributed to the discussion at Skeptical Science: "A Historical Perspective on Arctic Warming: Part One". Robert Way made the round in the blog-o-sphere with the paper Cowtan and Way (2013), where they studied the recent strong warming in the Arctic and suggested that that may explain a part of the recent slowdown in the warming of surface temperature.

Monday, 27 January 2014

Stoat has a nice new post explaining how peer review works in practice. The climate ostriches sometimes suggest that peer review is just there to keep their ideas out of the scientific literature and derogatively call it pal review. Well, peer review is nowadays practiced in all sciences, so that seems rather far fetched. Thinking about it, I would argue that peer review could actually help the climate ostriches. There is one caveat: they would have a valid critique. That is the bigger problem for them.

So what is peer review, what is its function in science and how could it help the climate ostriches?

How does it work

The short description of peer review at Stoat is:

For a working scientist, peer review is just part of the job. You write up your work, you show it to your colleagues ..., you send it to the best journal you think you can get away with, and eventually you get the reviews back. These will be a mixture of “please cite my paper” (usually disguised as “you need to consider X”), typos, and the occasional well-considered thoughtful comment that genuinely improves things. You sigh, you happily incorporate the thoughtful stuff, you work out how much of the not-very-helpful stuff you can get away with blowing off, and you resubmit ... And sometimes you get a reviewer who really really doesn’t like your paper for what you regard as invalid reasons, and you have to decide whether to fight to the death or go elsewhere.

Function in science

Peer review gives an article credibility. As such peer review is "just" a filter, it does not guarantee that an article is right. Many peer-reviewed articles contain errors, many ideas outside of the peer-reviewed literature are worthwhile. However, on average the quality of peer-reviewed work is better. Thus peer-reviewed work is more likely worthy of your attention. If you are a scientist and an idea/study is about something you are knowledgeable about there is no reason to limit yourself exclusively to peer-reviewed articles, but it is smart to prefer them.

Given that an important function of peer review is to give the article credibility, it is also logical that reviewers pay extra attention if an article makes strong claims, that is claims that clearly deviate from our current understanding. In an ideal world, without any time pressures, peer review would be perfect every instance. However, a run of the mill article by a well-known author is much less likely to contain problems.

I would argue that that should be no problem for the people making strong claims. Every claim should hold up the scrutiny of the reviewers any way. That may be more work, but such an article also brings much more acclaim and is thus worth some work. As quoted above, sometimes reviewers will block your beautiful manuscript. That has also happened to me and probably to any active scientist. Then you just go to another journal. If the idea is valid, you will find a place for it.

That peer review is not perfect may be more of a problem for seasoned scientists. I especially notice that well-written article, by native speakers, are more likely to contain small errors. The smooth language seems to make the reviewers less critical and the author is punished by publishing articles with embarrassing errors.

Saturday, 25 January 2014

I am a little late with this, I just came across the Week in review by Judith Curry. If there is one thing that annoys me about the way Curry communicates, it is her suggestive, but completely non-committal language. The exact opposite of what I am used to among scientists. The word "interesting" is one of her favorite suggestive words.

Here is a quote illustrating the problem. Curry writes:

Freezing is the new warming

RealClearPolitics has an interesting article Freezing is the new warming, that summarizes the current state of the public debate on climate change. Excerpts:

Or try refuting global warming. Temperatures have stopped warming for more than a decade? That’s just a temporary “pause” in the warming that we just know is going to come roaring back any day now. Antarctic ice is growing? That’s actually caused by the melting of ice, don’t you know. A vicious cold snap that sets record low temperatures? That’s just because the North Pole is actually warming. So if the winter is warm, that’s global warming, but if the winter is cold, that’s global warming, too. If sea ice is disappearing, that’s global warming, but if sea ice is increasing, that’s global warming.

Now we can see what they mean when the warmthers say that global warming is supported by an ironclad scientific consensus. The theory is so irrefutable that it’s unfalsifiable!

Which is to say that it has become a cognitive spaghetti bowl full of ad hoc rationalizations, rather than a genuine scientific hypothesis.

This is pure and utter nonsense. Let me just discuss the main point, all the other denier memes are debunked at Skeptical Science. It is very easy to falsify the theory of global warming by greenhouse gasses.

If there would be an unexplained temperature drop of one degree and it would stay there for a decade, the theory is completely dead. If the same thing happens to the ocean heat content, the theory is dead within a year.

RealClearPolitics is right in suggesting that anything that will actually happen is very unlikely to refute the theory. Quite of lot of basic science would need to be wrong. And RealClearPolitics is right in suggesting that it is not sufficient for something to happen what feelies intuitively feel should not happen in a warmer climate. You do need some actual proof that the phenomenon should behave that way. His blog is at least honestly called a political blog.

Judith Curry is very intelligent and has much experience as scientist. She naturally knows that this quote was nonsense, but also that her audience likes it. Thus she non-noncommittally calls it interesting.

My wish for 2014 is that Curry comes back to the scientific community and stops using the word "interesting" so much. The scientific way of trying to understand why there is a difference of understanding is making it clearer what you mean.